Hostname: page-component-586b7cd67f-r5fsc Total loading time: 0 Render date: 2024-11-23T03:28:19.911Z Has data issue: false hasContentIssue false
  • English
  • Français

The effects of short-term manipulation of thyroid hormone status coinciding with primary wool follicle development on fleece characteristics in Merino sheep

Published online by Cambridge University Press:  18 March 2011

M. L. McDowall ,
N. M. Edwards  and
P. I. Hynd
M. L. McDowall*
Affiliation:
School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy Campus, Roseworthy South Australia 5371, Australia
N. M. Edwards
Affiliation:
School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy Campus, Roseworthy South Australia 5371, Australia
P. I. Hynd
Affiliation:
School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy Campus, Roseworthy South Australia 5371, Australia
Get access

Abstract

Thyroidectomy surgery performed late in gestation results in perturbations in wool follicle development in foetal sheep, showing the importance of thyroid hormones for wool follicle development. The aim of this study was to determine the influence of transient manipulation of thyroid hormone status at a time corresponding with foetal primary wool follicle initiation. Pregnant Merino ewes (n = 12 per treatment) were treated daily between gestational days 55 and 64 with control (vehicle), exogenous thyroxine (T4) or propylthiouracil (PTU), an inhibitor of T4 synthesis, and conversion to the active form of the thyroid hormone (triiodothyronine). There were no significant differences in birth weight, gestational lengths and birth coat scores of the resultant lambs. The total primary and secondary follicle densities were significantly lower in lambs exposed to exogenous T4 compared with other treatments (P < 0.05). However, the T4 group displayed a higher proportion of mature secondary follicles (reflected by increased mature secondary follicle densities and mature secondary/primary follicle ratios) than the other treatment groups (P < 0.05). The skin morphology of the lambs differed 12 months later, with the T4 group having significantly higher total follicle densities compared with the PTU group, largely attributed to increased mature and total secondary follicle densities. However, this increase in wool follicle densities did not translate to differences in the fleece yields and weight, fibre diameter, staple lengths or any other fibre parameters. This study showed that transient manipulation of thyroid hormone status during foetal primary follicle initiation does have long-term consequences on the morphology of wool follicles, in particular the maturity of secondary wool follicles.

Keywords

wool folliclesheepthyroid hormoneswool follicle developmentfoetal development
Type
Full Paper
Information
animal , Volume 5 , Issue 9 , 05 August 2011 , pp. 1406 - 1413
Copyright
Copyright © The Animal Consortium 2011

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Atkins, P, Cohen, SB, Phillips, BJ 2000. Drug therapy for hyperthyroidism in pregnancy: safety issues for mother and fetus. Drug Safety 23, 229–244.CrossRefGoogle ScholarPubMed
Billoni, N, Buan, B, Gautier, B, Gaillard, O, Mahe, YF, Bernard, BA 2000. Thyroid hormone receptor beta1 is expressed in the human hair follicle. British Journal of Dermatology 142, 645–652.CrossRefGoogle ScholarPubMed
Carter, HB 1939. Fleece density and the histology of the Merino skin. Australian Veterinary Journal 15, 210–213.CrossRefGoogle Scholar
Carter, HB, Clarke, WH 1957. The hair follicle group and skin follicle population of Australian Merino sheep. Australian Journal of Agricultural Research 8, 91–108.CrossRefGoogle Scholar
Carter, HB, Hardy, MH 1947. Studies in the biology of the skin and fleece of sheep. IV. The hair follicle group and its topographical variations in the skin of the Merino foetus. Bulletin of the Council for Scientific and Industrial Research Australia 215, 1–41.Google Scholar
Chapman, RE, Hopkins, PS, Thorburn, GD 1974. The effects of fetal thyroidectomy and thyroxine administration on the development of skin and wool follicles of sheep fetuses. Journal of Anatomy 117, 419–432.Google ScholarPubMed
Cheron, RG, Kaplan, MM, Larsen, PR, Selenkow, HA, Crigler, JF Jr 1981. Neonatal thyroid function after propylthiouracil therapy for maternal Graves’ disease. New England Journal of Medicine 304, 525–528.CrossRefGoogle ScholarPubMed
Coelli, KA, Atkins, KD 1995. Fleece weight and fibre diameter relationships within and between Merino flocks. Proceedings of the Australian Association of Animal Breeding and Genetics 11, 587–590.Google Scholar
Ferguson, KA, Schinckel, PG, Carter, HB, Clarke, WH 1956. The influence of the thyroid on wool follicle development in the lamb. Australian Journal of Biological Science 9, 575–585.CrossRefGoogle Scholar
Gregory, IP 1982. Genetic studies of South Australian Merino sheep. 4. Genetic, phenotypic and environmental correlations between various wool and body traits. Australian Journal of Agricultural Research 33, 363–373.CrossRefGoogle Scholar
Hancock, TW, Mayo, O, Brady, RE 1979. Response to partial selection on clean fleece weight in South Australian strong-wool Merino sheep. IV.* Genetic parameters. Australian Journal of Agricultural Research 30, 173–189.CrossRefGoogle Scholar
Hardy, MH, Lyne, AG 1956. The pre-natal development of wool follicles in merino sheep. Australian Journal of Biological Science 9, 423–443.CrossRefGoogle Scholar
Hocking Edwards, JE 1999. Reduction in wool follicles prior to birth in Merino sheep. Reproduction, Fertility and Development 11, 229–234.CrossRefGoogle ScholarPubMed
Hopkins, PS, Thorburn, GD 1972. The effects of foetal thyroidectomy on the development of the ovine foetus. Journal of Endocrinology 54, 55–66.CrossRefGoogle ScholarPubMed
Hynd, PI 1994. Follicular determinants of the length and diameter of wool fibres. 2. Comparison of sheep differing in thyroid hormone status. Australian Journal of Agricultural Research 45, 1149–1157.CrossRefGoogle Scholar
Hynd, PI, Ponzoni, RW, Grimson, R, Jaensch, KS, Smith, D, Kenyon, R 1996. Wool follicle and skin characters – their potential to improve wool production and quality in Merino sheep. Wool Technology and Sheep Breeding 44, 167–177.Google Scholar
Jackson, N, Nay, T, Turner, HN, Newton, TH 1975. Response to selection in Australian Merino sheep. VII. Phenotypic and genetic parameters for some wool follicle characteristics and their correlation with wool and body traits. Australian Journal of Agricultural Research 26, 937–957.CrossRefGoogle Scholar
Moore, GP, Jackson, N, Isaacs, K, Brown, G 1996. Development and density of wool follicles in Merino sheep selected for single fibre characteristics. Australian Journal of Agricultural Research 47, 1195–1201.CrossRefGoogle Scholar
Moore, GP, Jackson, N, Isaacs, K, Brown, G 1998. Pattern and morphogenesis in skin. Journal of Theoretical Biology 191, 87–94.CrossRefGoogle ScholarPubMed
Nixon, AJ 1993. A method for determining the activity state of hair follicles. Biotechnic and Histochemistry 68, 316–325.CrossRefGoogle ScholarPubMed
Puchala, R, Prieto, I, Banskalieva, V, Goetsch, AL, Lachica, M, Sahlu, T 2001. Effects of bovine somatotropin and thyroid hormone status on hormone levels, body weight gain, and mohair fiber growth of Angora goats. Journal of Animal Science 79, 2913–2919.CrossRefGoogle ScholarPubMed
Rogers, GE 2006. Biology of the wool follicle: an excursion into a unique tissue interaction system waiting to be re-discovered. Experimental Dermatology 15, 931–949.CrossRefGoogle ScholarPubMed
Rosenfeld, H, Ornoy, A, Shechtman, S, Diav-Citrin, O 2009. Pregnancy outcome, thyroid dysfunction and fetal goitre after in utero exposure to propylthiouracil: a controlled cohort study. British Journal of Clinical Pharmacology 68, 609–617.CrossRefGoogle ScholarPubMed
Short, BF 1955. Developmental modification of fleece structure by adverse maternal nutrition. Australian Journal of Agricultural Research 6, 863–872.CrossRefGoogle Scholar
Smith, BT, Sabry, K 1983. Glucocorticoid-thyroid synergism in lung maturation: a mechanism involving epithelial–mesenchymal interaction. Proceedings of the National Academy of Science USA 80, 1951–1954.CrossRefGoogle ScholarPubMed
Toland Thompson, AC, Hebart, MC, Penno, NM, Hynd, PI 2007. Perinatal wool follicle attrition coincides with elevated perinatal circulating cortisol concentration in Merino sheep. Australian Journal of Agricultural Research 58, 748–752.CrossRefGoogle Scholar
Villar, D, McMillen, SR, Dicks, P, Rhind, SM 2000. The role of thyroid hormones and prolactin in the control of fibre moult and associated changes in hair follicle activities in cashmere goats. Australian Journal of Agricultural Research 51, 407–414.CrossRefGoogle Scholar
Wallace, CE, Simpson-Morgan, MW, McCullagh, P 1994. Retarded and excessive development of skin appendages in fetal lambs in response to thyroidectomy before wool follicle appearance. Journal of Compariative Pathology 110, 275–286.CrossRefGoogle ScholarPubMed
Williams, AP, Thornberry, KJ, Gilmore, AR 1990. The activity of the thyroid glands in relation to genetic differences in wool production. Australian Journal of Agricultural Research 41, 573–581.CrossRefGoogle Scholar